The present invention generally relates to the art of sports bicycles, and more specifically to a novel and unique strapless shoe and pedal assembly for detachably locking a bicyclist's shoes to the pedals of the bicycle.
The art has long recognized the desirability of increasing the period during which a rider can apply effective force to the pedals of a bicycle. When utilizing a conventional bicycle pedal, the rider is only able to exert a driving force during an arc of pedal movement of less than 180 degrees for each complete revolution of the crank axle; and maximum driving force is exerted only through an arc of something less than about 90 degrees.
To increase the period during which the propelling force is applied, the art has proposed various means for positvely attaching the bicyclist's shoes to the pedals so as to enable the rider to develop work, or exert cranking force, on the upstroke as well as on the downstroke of each pedal cycle. Thus, while progressing through the downstroke of one pedal, the cyclist is able to apply cooperating force on the other pedal through its upstroke.
While it is highly desirable to lock, or secure, the shoes to the pedals for road and racing bicycles, such a system is equally advantageous for mountaineering bicycles used to climb steep hills and traverse rough terrain where loss of positive shoe to pedal contact, or engagement, not only reduces driving force, but also may result in serious injury to the rider.
Numerous devices have been proposed for accomplishing this desirable rigid securement. Included, for example, are strap and/or clip arrangements which are attached to the pedal and extend over the top of the shoe and sometimes the instep of the rider's shoes. Although such devices have the advantage of being useful regardless of the kind of shoe worn by the rider, they have an undesirable aspect in that they tend to dig uncomfortably into the upper portions of the rider's feet and can also disengage from the pedal under disadvantageous circumstances.
The current industry standard expedient to overcome the disadvantages of the prior art is the "Look" system, developed by Look America, Inc. of Highland Park, Ill. The system is evolved from the art of ski bindings and in general comprises a cleat fixed to the bottom of each shoe and a cleat retention mechanism integral with each pedal. The cleat retention mechanism comprises a fixed rear cleat retention plate and a spring loaded front cleat retention plate which lock onto the shoe cleat when the rider steps down onto the pedal.
Further examples of downwardly extending cleats and retaining arrangements are disclosed in U.S. Pat. No. 550,409, issued Nov. 26, 1985 to Hanson and U.S. Pat. No. 4,298,210, issued Nov. 3, 1981 to Lotteau et al. These latter systems feature bayonet locking arrangements whereby the rider steps down on the pedal and then rotates his foot through an angle to make the connection.
The Look system is satisfactory for racing and other applications in which the rider will not be expected to dismount from the bicycle and walk for any significant distance. However, walking on shoes with cleats attached is extremely uncomfortable, and the cleats will become damaged quickly if subjected to such abuse. For this reason, a retaining arrangement including sole mounted cleats is unacceptable for mountaineering bicycle applications wherein the rider must dismount from time to time and push or carry the bicycle over rough terrain.
Various arrangements which do not include sole-mounted cleats are found in the prior art. U.S. Pat. No. 575,712, issued Jan. 26, 1897 to Hamilton et al., U.S. Pat. No. 620,266, issued Feb. 28, 1899 to Wodiska and U.S. Pat. No. 616,167, issued Dec. 20, 1898 to Walker, disclose mechanical devices which are arranged to clamp over or retain the side edges of the soles of the rider's shoes. More specifically, these systems comprise clamps or lips which are moved through linkage or cam mechanisms inwardly into clamping engagement with the shoe when the rider steps downwardly onto the pedals.
Although of considerable utility, these devices are not designed for use with modern cycling shoes made of lightweight materials since they tend to dig into and rapidly damage such materials. These devices are further unacceptable for mountaineering bicycle applications as constant downward pressure on the pedals is required for the linkage mechanisms to affect lateral clamping of the shoes, and such downward pressure is essentially lacking during upward movement of the pedals while the bicycle is climbing a steep hill.
A major drawback of all retention systems known heretofore is that none of them includes a provision for disengaging the retention mechanism for conventional operation as non-retaining pedals without disassembly of the entire retention mechanism.
It is therefore an object of the present invention to provide a combined shoe and strapless pedal for a sports bicycle which securely retains the rider's shoes to the pedals without the expedient of downwardly extending cleats mounted on the soles of the shoes.
It is a further object of the present invention to provide a road pedal assembly which eliminates the discomfort associated with prior art strap and clamp retention arrangements.
It is a further object of the present invention to provide a road pedal assembly which enables the retention mechanism to be partially or entirely disengaged with minimal effort.
Other objects, together with the foregoing, are attained in the embodiments described in the following description and illustrated in the accompanying drawings.